In recent years small buses and vans have been used by families and small groups, in traveling from one part of the country to another, using the vehicle for living quarters at night and during stopovers at vacation and recreation places. In most cases, small buses and vans are not of a sufficient height to permit an adult to stand erect or to move comfortably from place to place in the vehicle, and, as a result, various attempts have been made to make extensible roofs for these vehicles. Existing extensible roof designs have to some extent been unsatisfactory in that difficulty has been experienced in extending and retracting the associated roofs. Further, considerable physical exertion has been necessary to raise or lower the roofs to the fully extended or retracted position. Consequently, these designs have a propensity to drop rather abruptly when lowering, as well as a relative difficulty encountered in elevating the same to a fully extended position. As a result, several designs have attempted to facilitate and improve upon the extending and retracting operation.
As an example, U.S. Pat. No. 3,770,314 to Charles L. Borskey discloses an extensible roof assembly utilizing one tension spring to assist in the operations of extending and retracting the roof.
U.S. Pat. No. 3,619,001 to Charles L. Borskey teaches an extensible roof assembly utilizing several tension springs to assist in the elevation of the roof to its fully extended position.
U.S. Pat. No. 3,582,130 to Charles L. Borskey relates to an extensible roof assembly utilizing one tension spring to assist with the operations of extending and lowering the roof.
U.S. Pat. No. 3,212,813 to William L. Peterson et al discloses an extensible roof assembly employing a tension spring device to assist with the elevation of the roof assembly.
U.S. Pat. No. 2,843,418 to Charles W. Gray relates to an expandable camping trailer employing a helical tension spring to counterbalance the weight of the cover.
U.S. Pat. No. 2,729,497 to Arleigh A. Runyan teaches a collapsible camping trailer body utilizing a gear shifting mechanism that may be operably connected with rotatable screw shafts to facilitate raising of the roof.